Question 1 of 33

1. What is the function of power controller in drive circuits?

It maintain the torque at low voltage conditions

It sounds an alarm in no load conditions

It detects the overloading condition of motor

It reduce motor current during transient operation

Question 1 of 33

Question 2 of 33

2. What is the purpose of JOG key in control panel of D.C drive?

Inching operation

Reverse the direction of motor

Stop the motor

Restart the motor

Question 2 of 33

Question 3 of 33

3. Which device controls the speed of A.C motor in A.C drive?

COMMS technology box

Field supply unit (FSU)

Microprocessor based electronic device

Speed feedback technology box

Question 3 of 33

Question 4 of 33

4. How can the base speed of D.C shunt motor be increased by using D.C drive?

By reducing the armature voltage

By increasing the field current

By reducing the field current

By increasing the supply voltage

Question 4 of 33

Question 5 of 33

5. What is the purpose of PROG/DATA button in BOP of AC drive?

To display the data status of frequency and current

To display the data direction of rotation forward/REV

To change the parameter setting

To store the entered data and factory stored data

Question 5 of 33

Question 6 of 33

6. What is the name of the characteristic curve in D.C drive?

Field current Vs armature current characteristic

Speed Vs armature current characteristic

Torque Vs field current characteristic

Speed Vs torque characteristic

Question 6 of 33

Question 7 of 33

7. What is the purpose of LCD on basic operator panel in D.C drive?

Monitor the parameter

Display availability of supply

Indicate the fault

Display the speed

Question 7 of 33

Question 8 of 33

8. Which type of sensing unit is employed in drive systems?

Photo voltaic cell

Opto coupler

Speed sensing

Resistance temperature detector

Question 8 of 33

Question 9 of 33

9. Which power modulator is used in the electric drive system?

Frequency multiplier

Servo controlled voltage stabilizer

Cyclo converters

Phase sequence indicator

Question 9 of 33

Question 10 of 33

10. What is IGBT in VF drive?

Field supply switching device

D.C bus switching device

Rectifier switching device

Inverter switching device

Question 10 of 33

Question 11 of 33

11. What is the full form of B.O.P in D.C drive?

Basic Operational Panel

Basic Operation Programme

Bridge Operation Panel

Bridge Operator Programme

Question 11 of 33

Question 12 of 33

12. What is electric drive?

A device used as prime mover for generator

A device converts A.C to D.C supply

An electro mechanical device for controlling motor

A machine converts mechanical energy into electrical

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Question 13 of 33

13. What is the advantage of AC drive compared to DC drive?

Requires less space

Fast response and wide speed range of control

Power circuit and control circuits are simple

Installation and running cost is less

Question 13 of 33

Question 14 of 33

14. What is the purpose of LCD in Basic Operator Panel (BOP) in AC drive?

Indicate the display error in reading

Indicate the incorrect operation of BOP

Indicate the status of drive

Monitor the parameter of AC drive

Question 14 of 33

Question 15 of 33

15. Why is it necessary to keep V/F ratio constant in a drive?

Keep the stator flux maximum

Maintain the speed of motor constant

Maintain the rated torque at all speeds

Maintain the rotor current minimum

Question 15 of 33

Question 16 of 33

16. Which drive is classified according to mode of operation?

Continuous duty drive

Group drive

Manual drive

Individual drive

Question 16 of 33

Question 17 of 33

17. Which type of machine in industries is provided with multi-motor electric drive?

Rolling machine

Air Compressor

Shearing machine

Heavy duty electric drilling machine

Question 17 of 33

Question 18 of 33

18. What is the name of the component marked as 'X' in the block diagram of AC drive?

Rectifier

A.C motor

Inverter

D.C bus

Question 18 of 33

Question 19 of 33

19. What is the function of IGBT in AC drive?

Smoothening incoming A.C supply

Controls the power delivered to the motor

Stabilize the output voltage from the rectifier

Converts incoming A.C power into D.C power output

Question 19 of 33

Question 20 of 33

20. Which is the application of single quadrant loads operating in first quadrant in drives?

Elevators

Conveyors

Centrifugal pumps

Hoists

Question 20 of 33

Question 21 of 33

21. How can constant torque be obtained from armature and field controlled drives?

By reducing the field current

By increasing the field current

By controlling the armature voltage

By reducing the armature current

Question 21 of 33

Question 22 of 33

22. Why are A.C drives mostly used in process plants?

Very high starting torque

Maintenance free long life

Robust in construction

Easy to operate

Question 22 of 33

Question 23 of 33

23. Which is the correct sequence operation of key button in BOP of AC drive to change the direction of rotation?

Press ON → REV → OFF → ON

Press OFF → REV → ON

Press ON → REV → ON

Press ON → OFF → REV → ON

Question 23 of 33

Question 24 of 33

24. Which control system is used for Eddy current drives?

Slip controller

Rectifier controller

DC chopper controller

AC voltage controller

Question 24 of 33

Question 25 of 33

25. Which control system consumes very low power for motion control in AC and DC motors?

Field control

Drives control

Armature control

Voltage control

Question 25 of 33

Question 26 of 33

26. Which is proportional to the torque in D.C motor?

Back e.m.f

Field current

Armature current

Terminal voltage

Question 26 of 33

Question 27 of 33

27. What is the function of VSI drives?

Converts D.C to D.C

Converts A.C to A.C

Converts A.C to D.C

Converts D.C to A.C

Question 27 of 33

Question 28 of 33

28. What is the main use of A.C drive?

Group drive motors

High starting torque

Control stepless speed in motors

Interlocking system in industries

Question 28 of 33

Question 29 of 33

29. Which is the classification of drive according to dynamics and transients?

Short time duty drive

Automatic control drive

Variable position control drive

Intermittent duty drive

Question 29 of 33

Question 30 of 33

30. What is the disadvantage of DC drive?

More expensive than AC drive for high capacity motor

More complex with a single power conversion

Installation of DC drives is more complicated

Not suitable for high speed operation

Question 30 of 33

Question 31 of 33

31. Why are A.C drives better suited for high speed operation?

No brushes and commutation

Robust in construction

Having lighter gauge winding

High starting torque

Question 31 of 33

Question 32 of 33

32. What is the reason for using shielded cable for connecting low level signal circuits in DC drives?

Easy for connection

Eliminates the electrical interference

Protects from mechanical injuries

Good appearance

Question 32 of 33

Question 33 of 33

33. What is the function of Field Supply Unit (FSU) in DC drive?

Provides a constant voltage to the field winding of motor

Provides variable voltage to the field winding of motor

Provides a constant voltage to the armature of the motor

Produces required firing current to the firing circuit

Question 33 of 33